Combines non-contact voltage and light detection with 869 MHz RF (radio frequency) transmission technology. It enables a single user to identify mid-run wires and to find the breaker that powers a circuit or light fixture without having to connect directly to the wires in the cable. Easy-to use. Clamp the transmitter directly onto installed wiring to detect voltage. The receiver alerts the user at the breaker panel with a voltage-present LED indicator and audible beep 3. Alerts cease when the right circuit breaker is switched off or a junction splice is opened in the circuit. The RT32 is a convenient must-have tool for electricians, plumbers, general contractors, do-it-yourselfers, kitchen and bath remodelers, lighting installers, handymen and anyone who needs a virtual electrician's helper. Includes transmitter, receiver, remote clamp-style probe, 4 AAA batteries and pouch case.